Australian authorities believe Mohammad Ali Baryaleihas a trusted position in Islamic State operational command.

ABC

Police have issued an arrest warrant for a former Kings Cross nightclub bouncer believed to be Australia's most senior member of the Islamic State (IS) militant group in Syria and Iraq, following an investigation by the ABC's 7.30 program.

Authorities say Mohammad Ali Baryalei, 33, has used a trusted position in IS operational command to funnel more than half of the 60 Australians currently fighting in the wars.

Counter-terrorism sources have told 7.30 Baryalei recruited a who's who of Australian IS fighters, including senior fighters Mohamed Elomar and Khaled Sharrouf, who has posted pictures online of his seven-year-old son holding a severed head in Syria, as well as videos of himself and Elomar executing prisoners in Iraq.

Authorities say Baryalei has also facilitated the recruitment of at least two 17-year-old boys and at least seven Australians who have gone on to be killed in Syria and Iraq.

In a statement released to 7.30, the Australian Federal Police say an arrest warrant has been issued against Baryalei for "terrorism-related activity".

"Should Baryalei return to Australia, this warrant authorises law enforcement to arrest him immediately," an AFP spokesman said.

"As this matter is ongoing it would not be appropriate for the AFP to comment further."

Baryalei is from an aristocratic family from Afghanistan who came to Australia as refugees when he was a child.

The 33-year-old was an aspiring actor who had a fleeting appearance on the true-crime series, Underbelly, but years ago turned to radical Islam in Sydney.

Baryalei became a leader of the Street Dawah preaching movement in Sydney, where he formed a cell of jihadists.

He proselytised with at least five men who went on to die in Syria and Iraq and many more who are still fighting.

According to court documents, Baryalei arrived in Turkey in April 2013 and set up base at the Syrian border, where he initially recruited Australians to the Al Qaeda group, Jabhat Al Nusrah.

However, counter-terrorism sources say he became a key Australian operative for IS early this year.

Baryalei's family has told 7.30 he denies he is fighting and maintains he is living a peaceful life in Turkey.

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The road to radicalisation

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In January 2014, a young Australian couple was gunned down in Aleppo by rival rebel Syrian forces.Amira Karroum and her husband Tyler Casey were devout Muslims who travelled to Syria to join the global jihad.But how do a boy from the Brisbane suburbs and a girl from the Gold Coast beaches end up dead in one of the world's most brutal conflicts?

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Amira Karroum was born to a New Zealand mother and a secular Muslim father, who fled Lebanon to Australia and founded a multi-million-dollar restaurant business on the Gold Coast. She attended the exclusive Gold Coast Anglican private girls' school St Hilda's, before going on to study graphic design at QUT.Amira's teen years sunbathing on the beach, going to nightclubs and working at Sea World were a world away from the radical cause she would take up a few years later.

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Tyler Casey was born in Adelaide in 1990. As a small child he moved to Redcliffe, just north of Brisbane, where his mother married a recovering drug addict. Casey and his three younger half-brothers had a tumultuous upbringing in a fundamentalist Christian home.At 13, he moved with his mother to the United States. Separated from his younger brothers, he became involved in gangs and petty crime in the city of Colorado Springs. It was there he began his first steps on the path that would lead to an unmarked grave in Syria.

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Unbeknownst to his family, during his time in the US, Casey began to associate with followers of a senior Al Qaeda Anwar Al Awlaki, who had previously been based in Colorado and later died in Yemen; Australian authorities believe he became an international emissary for Al Qaeda. From 2008, he was paid by Al Qaeda in the Arabian Peninsula to travel to Egypt and Yemen, where US intelligence agencies report he was trained for warfare. He was also sent to South Africa for religious training in 2011, where he was filmed in the audience of a sermon by one of Syria's most prominent anti-government sheikhs, Muhammad Al Yaqoubi.

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Amira and Casey's paths crossed after each moved to Sydney. In her late teens, Amira moved with her sister to be closer to her Muslim relatives in Sydney's west.One of her cousins was Fadl Sayadi, who served five years in jail for being a senior player in the biggest terrorism plot in Australia's history. Another cousin was Bilal Sayadi, who had a history of crime dating back to his teens, including bashings, drug offences and a shooting.Casey had taken on the name Yusuf Ali and became a street preacher, converting Australians to Islam with other devout young men involved in the Street Dawah movement.It was through Street Dawah that he became close friends with another street preacher, Bilal Sayadi.

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Bilal Sayadi arranged a marriage between Amira and Casey and a romance blossomed - but police soon discovered the marriage was part of a bigger plot. For the couple, it was another step along the path to becoming a soldier of Islam.Amira began posting increasingly extreme statements to Facebook, writing "the hereafter is coming" and "Jannah [or paradise] is my destination". Another post said "democracy is cancer, Khilafah [the Islamic caliphate] is the answer".Months after the pair married, Casey told friends he was going to fight alongside Al Qaeda and wouldn't be returning to Australia or the US.Casey's stepfather reported his plan to the Australian authorities, but on June 29, 2013 he flew to Turkey via Singapore.

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During his time at Street Dawah, Casey had met fellow jihadist Mohammad Ali Baryalei, a leader of the Street Dawah movement who would emerge as a pivotal figure drawing young Australians to Syria.It was Baryalei, now based in Syria, Iraq and Turkey, who would facilitate Casey's journey to the Syrian battlefield, along with three other young Australians.Australian authorities say Baryalei has become the most senior Australian member of the Islamic State militant group in Syria and Iraq, responsible for funnelling at least half of the 60 Australians currently fighting there onto the frontline. Family of the 33-year-old Afghan refugee and former Kings Cross nightclub bouncer say he claims to be living a peaceful life in Turkey.

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Phone calls intercepted by police tell the story of the group's journey to the battlefield.From Turkey, they crossed the border to Syria in early July, where they were given battle training by Jabhat Al Nusra, an Al Qaeda affiliate fighting Assad's forces in Syria.As with this latest generation of jihadists, Casey embraced technology from the frontline, staying in close contact with his brother, showing off his cache of weapons - including AK-47s and hand grenades via Skype.

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Meanwhile, Amira was planning on joining her husband, telling her father she wanted to be a fighter.Under the guise of a trip to visit friends in Denmark, which was funded by her cousin Bilal Sayadi, she planned to make her way south to Syria.Police halted her first effort to leave the country, but the next day, with the assistance of her lawyer, she left for Denmark, where she met up with other Islamists making the journey to Syria.Amira and Casey were reunited in January 2014, but instead of fighting Assad, they became embroiled in a fierce power struggle between rival rebel groups.

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Just days after Amira's arrival in the rebel stronghold of Aleppo, they were ambushed and executed in a makeshift home they shared with a Somali couple.Australian authorities say in a brutal takeover of their Australian Jabhat Al Nusra contingent, the house was surrounded by IS militants wielding automatic weapons and Amira and her husband were killed in a blaze of gunfire.Her father had a heart attack upon hearing the news, saying he received a call from Syria telling him his daughter's body had been dismembered and the Somali couple was buried alive.Within days, Casey's fellow fighters had joined Islamic State.